An efficient approach to extract nanocrystalline cellulose from sisal fibers: Structural, morphological, thermal and antibacterial analysis

Abstract

Nanocellulose has been proposed by many researchers as a suitable bio-reinforcement material for the development of sustainable bio-nanocomposites in advanced applications due to its excellent properties. Conventional techniques for extracting nanocellulose from plant biomass are time-consuming and involve chemical wastage. This study aims to extract nanocellulose using simple processes with minimal consumption of chemicals in a minimum time. In the present work, cellulose nanocrystalline has been extracted from sisal fibers efficiently by chemical treatment assisted with steam explosion and mechanical grinding. The morphology of extracted sisal cellulose nanocrystalline (CNC-S) was analyzed by FESEM, whereas the DLS, TEM and AFM confirmed its nanosize. The average aspect ratio and zeta potential (ζ) of CNC-S were measured as 7.4 and −14.3 mV, respectively. The XRD analysis indicated that the crystallinity of the fibers considerably improved from 48.74 % for untreated fibers (UT-S) to 74.28 % for CNC-S. The chemical structure of the fibers was changed as hemicellulose and lignin were found to be eliminated after the chemical treatment which FTIR confirmed. From TGA-DTG results, it was observed that CNC-S has good thermal stability. It was also noticed that CNC-S did not show any antibacterial properties against E. coli and S. aureus due to the complete removal of lignin. This study suggests that the present extraction process can be considered as an efficient process to convert fibers into high performance nanocellulose to be used as potential reinforcing material in advanced applications.